ZHCSNB6A April 2021 – February 2022 TPS23882B
PRODUCTION DATA
Unlike auto mode, which still requires a host to initialize the TPS23882B operation through a series of I2C commands, there is no host or I2C communication required when the device is in configured in autonomous mode.
During power up, the resistance on the AUTO pin (RAUTO) is measured, and the device is pre-configured according to Table 9-15. The port automatically performs detection and classification (if valid detection occurs) continuously on all ports. Port power is automatically turned on based on power allocation settings in register 0x29 if a valid classification is measured.
For applications that still require port telemetry, the I2C functionality is still supported in autonomous mode.
A 10-nF capacitor is required in parallel with RAUTO to ensure stability in the autonomous mode selection.
The auto pin resistance (RAUTO) is measured following a device reset (assertion of the RESET pin or RESAL bit in register 0x1A). The device only measures (RAUTO) and pre-configures the internal registers during power up (VVPWR and VVDD rising above their respective UVLO thresholds).
The device SRAM must be programmed to support applications that desire to remove a device from autonomous mode after having initially powered up in autonomous mode.
A device running from the internal ROM (SRAM unprogrammed) in autonomous mode turns off and automatically resume discovery and power on any valid loads following the assertion of the RESET pin, I2C register 0x1A RESAL or RESPn bits, or a mode off command. Whereas a device running in autonomous mode with the SRAM programmed turns off and remains inactive until the host re-enables the ports through the I2C bus.